Building envelopes of certain commercial and mixed use residential buildings include a curtain wall. The curtain wall of a building defines the appearance of the building and, more importantly, separates the interior controlled or conditioned space from the outside environment. The curtain wall is usually formed from a plurality of curtain wall panels that typically contain glass, metal, and/or stone. The curtain wall panels are attached to the building's structural elements via anchors and curtain wall panel hanging brackets (sometimes referred to as curtain wall panel brackets or panel brackets). The anchors are located at discrete attachment points along the edges of the building's concrete floor slabs. The anchors typically include embedments (sometimes referred to as embeds) that are each cast into a concrete floor slab and that may be located on the top of the slab, on the face of the slab, or beneath the slab. A panel bracket is attached to each embedment, aand a curtain wall panel is hung from each panel bracket.
For a given concrete floor slab, before the concrete that forms that concrete floor slab is poured into the concrete form, an array of rebar, metallic cables, and/or other material used to reinforce the concrete floor slab is installed within the concrete form. Embedments are then positioned along an edge of the concrete form by a one or more workers using a tape measure and control lines provided by the general contractor. That is, the worker typically uses the tape measure to hand measure where to position each embedment along the edge of the concrete form using the control lines for reference, though in certain instances the embedments are positioned along the edge of the concrete form with the aid of survey equipment.
This installation process requires another measurement by the worker to assure the embedment has the proper edge spacing from the concrete form (i.e., to ensure the embedment is located at the proper distance from the edge of the concrete form). More specifically, after determining the position along the edge of the concrete form at which to attach the embedment, the worker must then use the tape measure to hand measure the distance of the embedment from the edge of the concrete form. The worker then anchors the embedment into place by either nailing the embedment to the concrete form, wire tying the embedment to rebar, or wire tying the embedment to scraps of lumber and then nailing the lumber to the concrete form such that the anchored embedment has the proper edge spacing from, and is positioned at the desired position along the edge of, the concrete form.
Concrete is then poured into the concrete form, typically via a high pressure concrete pumping hose. Concrete pumping hoses are heavy and unwieldy, and typically require multiple workers to control and operate the concrete pumping hose while walking on and around the rebar, metallic cables, and/or other reinforcing materials within the concrete form. As and after the concrete is being poured (pumped) into the concrete form, several workers level the poured concrete, which again involves the workers walking on and around the rebar, metallic cables, and/or other reinforcing materials. This movement, shifting, and jostling of the rebar, metallic cables, and/or other reinforcing materials, along with the vibration of the concrete pumping hose and the movement of the poured concrete itself, is problematic because it may alter the position of one or more of the embedments or dislodge one or more of the embedments.
Sometime after the concrete has been poured, each embedment must be located and exposed, which sometimes requires workers to chip away any concrete that may be covering the embedment. After the embedments are located and exposed, a survey is conducted to determine whether any of the embedments are potentially problematic. More specifically, the survey is conducted to determine whether any embedments are missing, any embedments are buried too deep within the concrete floor slab, any embedments are improperly positioned or misaligned, and/or whether any embedments conflict with other features of the building, in which case a panel bracket may not be able to be safely or properly mounted to that embedment. After the survey is completed, any problematic embedments must be fixed before construction can continue.
After any problematic embedments are fixed, workers attach a panel bracket to each embedment using fasteners. Certain curtain wall panels include attachment fixtures that “hang” onto the panel brackets. These attachment fixtures often include a mechanism that enables some level adjustment to aid in leveling the curtain wall panels. These leveling mechanisms are seldom used, however, because they increase the time it takes to the hang the curtain wall panels, thereby increasing installation costs due to labor and equipment (such as cranes). As a result, the panel brackets are usually leveled per floor prior to the installation of the curtain wall panels.
More specifically, for each floor of the building, the panel brackets on that floor are leveled relative to one another such that they are all planar and at a same elevation so the installed curtain wall will be level after the curtain wall panels are craned into position. The leveling of the panel brackets relative to one another is typically accomplished through the use of shims of different thicknesses. More specifically, to level a particular panel bracket, one or more workers (who may have different levels of experience) pick one or more shims from a variety of different sized shims of different materials and manually insert the shims between various areas of the panel bracket and the concrete to level that panel bracket.
The manual shimming process is cumbersome and time consuming, which increases labor costs and delays construction. Further, the variation in skill level among the workers who shim the panel brackets leads to inconsistent and, in some instances, improper shimming, which has costly and sometimes dangerous consequences. Additionally, shims are an added expense, and must be purchased in advance in large enough quantities to service the entire building. If adequate inventory is not maintained, construction will be delayed while more shims are ordered and shipped. In certain instances, custom shims may be required, which adds another layer of expense.
In addition to increasing costs, in some instances improper or inconsistent shimming adversely affects the integrity of the panel brackets and the installed curtain wall. For instance, in certain cases in which one or more panel brackets are improperly or poorly shimmed: the mounting bolts (which are used to mount the panel bracket to the embedment) may, over time, bend out of alignment; the embedment channel itself may, over time, uncurl; and the shims themselves may, over time, shift. These occurrences are likely to cause the curtain wall panels themselves to shift and become uneven. Uneven curtain wall panels create leaks, broken glass, and result in an unappealing building façade.
There is a need for new apparatuses and methods for leveling panel brackets that solve the above problems.